docs: def rsync(from_path, to_path, flags='-r', options=None, timeout=None):
      """Replicate the contents of a path"""
      options = options or ['--delete', '--executability']
      cmd = ['/usr/bin/rsync', flags]
      if timeout:
          cmd = ['timeout', str(timeout)] + cmd
      cmd.extend(options)
      cmd.append(from_path)
      cmd.append(to_path)
      log(" ".join(cmd))
      return subprocess.check_output(cmd, stderr=subprocess.STDOUT).decode('UTF-8').strip()